Usage
This combination drug is primarily prescribed for the short-term symptomatic treatment of heartburn and acid regurgitation associated with acid indigestion and sour stomach. It is categorized as an H2 receptor antagonist (specifically, famotidine) combined with antacids (calcium carbonate and magnesium hydroxide). Famotidine decreases stomach acid production by blocking histamine H2 receptors in the stomach lining. Calcium carbonate and magnesium hydroxide neutralize existing stomach acid.
Alternate Names
This combination is often referred to as famotidine/calcium carbonate/magnesium hydroxide. Popular brand names include Pepcid Complete and Dual Action Complete.
How It Works
Pharmacodynamics: Famotidine competitively inhibits the action of histamine at the H2 receptors of the parietal cells, reducing basal and nocturnal gastric acid secretion stimulated by food, caffeine, insulin, betazole, and pentagastrin. Calcium carbonate and magnesium hydroxide are antacids that directly neutralize gastric acid, providing rapid symptom relief. The magnesium component can have a laxative effect, while the calcium can cause constipation. These opposing effects often balance each other out, resulting in normal bowel movements.
Pharmacokinetics: Famotidine is incompletely absorbed from the gastrointestinal tract. It is minimally metabolized in the liver and primarily excreted unchanged in the urine. The bioavailability of famotidine can be slightly reduced by the antacids in the combination product, though this is generally not clinically significant. Calcium carbonate and magnesium hydroxide react with stomach acid to form soluble salts, some of which are absorbed systemically. Unabsorbed antacids are excreted in the feces.
Mode of Action: Famotidine acts at the cellular level by binding to H2 receptors on parietal cells, preventing histamine from stimulating acid secretion. Calcium carbonate and magnesium hydroxide neutralize acid through a chemical reaction in the stomach lumen.
Receptor Binding/Enzyme Inhibition: Famotidine binds to H2 receptors. No significant enzyme inhibition is associated with this combination.
Elimination: Famotidine is primarily excreted renally. Calcium and magnesium from the antacids are partially absorbed and excreted renally; the unabsorbed portion is eliminated fecally.
Dosage
Standard Dosage
Adults and children 12 years and older:
One chewable tablet thoroughly chewed as needed for symptom relief, up to twice daily. Do not exceed two tablets in 24 hours. The duration of treatment should not exceed 14 days without consulting a physician.
Children (under 12 years):
The safety and efficacy have not been established in children under 12.
Special Cases:
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Elderly Patients: No specific dose adjustment based on age is generally necessary, but renal function should be monitored.
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Patients with Renal Impairment: Dosage adjustment may be required in moderate to severe renal impairment (creatinine clearance < 60 mL/min). Consult the famotidine prescribing information for specific recommendations.
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Patients with Hepatic Dysfunction: No specific dose adjustment is typically required for famotidine. However, caution should be exercised.
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Patients with Comorbid Conditions: Use with caution in patients with severe coexisting illnesses. For example, concomitant use with certain medications can require adjustments.
Clinical Use Cases
This combination is not indicated for use in clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
Refer to the sections on renal/hepatic dysfunction and special cases above.
Side Effects
Common Side Effects
Headache, dizziness, constipation, diarrhea.
Rare but Serious Side Effects
Allergic reactions (rash, itching, swelling, severe dizziness, difficulty breathing), changes in heartbeat, thrombocytopenia, agranulocytosis, aplastic anemia, pancytopenia.
Long-Term Effects
Long-term use of this combination can potentially mask symptoms of serious underlying conditions and should be avoided. Prolonged use of high doses of calcium carbonate can lead to hypercalcemia and milk-alkali syndrome, especially in patients with renal impairment.
Adverse Drug Reactions (ADR)
Hypersensitivity reactions, arrhythmias, hepatotoxicity.
Contraindications
Hypersensitivity to any component of the drug, severe renal failure, trouble or pain swallowing food, vomiting with blood, or bloody/black stools.
Drug Interactions
This combination can interfere with the absorption of numerous medications including: ketoconazole, itraconazole, tetracyclines, certain quinolones. Antacids can also affect the absorption of other drugs by altering gastric pH. Consult a drug interaction database for a comprehensive list of potential interactions.
Pregnancy and Breastfeeding
Consult a physician before use during pregnancy or breastfeeding.
Drug Profile Summary
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Mechanism of Action: Famotidine: H2 receptor antagonist. Calcium carbonate/magnesium hydroxide: Antacids.
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Side Effects: See Side Effects section.
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Contraindications: See Contraindications section.
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Drug Interactions: See Drug Interactions section.
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Pregnancy & Breastfeeding: Consult physician before use.
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Dosage: See Dosage section.
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Monitoring Parameters: Renal function, serum calcium, magnesium, and phosphate levels (with prolonged use or high doses).
Popular Combinations
This product itself is a combination, and combining it further with other drugs is generally not recommended without physician supervision.
Precautions
Pre-existing medical conditions should be assessed, and patients should be advised to consult a physician if symptoms persist or worsen. Exercise caution in pregnancy, during breastfeeding, and in pediatric and elderly populations, taking into account renal function.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Calcium + Famotidine + Magnesium?
A: For adults and children 12 years and older, chew one tablet completely as needed for symptom relief, up to twice a day. Do not exceed two tablets in 24 hours.
Q2: Can this combination be used long-term?
A: No, it is intended for short-term use (up to 14 days). Consult a physician for ongoing symptoms.
Q3: What are the contraindications to using this medication?
A: Contraindications include hypersensitivity, severe renal failure, difficulty swallowing, and gastrointestinal bleeding.
Q4: What are the major drug interactions with this combination?
A: It can reduce the absorption of several medications like ketoconazole, itraconazole, tetracyclines and some quinolones.
Q5: Can pregnant or breastfeeding women use this combination?
A: Consult a physician before using this drug during pregnancy or breastfeeding.
Q6: Are there any special dosage considerations for patients with kidney disease?
A: Yes, dose adjustment may be necessary in moderate to severe renal impairment.
Q7: How does this medication work to relieve heartburn?
A: It combines the acid-reducing effects of famotidine with the acid-neutralizing effects of calcium carbonate and magnesium hydroxide.
Q8: What are the common side effects of this combination?
A: Common side effects may include headache, dizziness, constipation, and diarrhea.
Q9: What should patients do if their symptoms do not improve?
A: If symptoms persist or worsen after 14 days of use, patients should discontinue the medication and consult a physician.
